A pre-fabricated construction panel for use on an external surface and/or as part of a building or construction is disclosed in GB2479023B. The panel comprises a water repellant particulate board.
When fiber cement board is used, the fiber cement board shows at least two reasons for dilatation in the directions parallel to the fiber cement board.
When the fiber cement board is exposed to changing humidity, rain, etc, the fiber cement board will show a dilatation due to the changing humidity of the board itself. This is typically a reversible dilatation. Over time, carbonatation of the fiber cement board will cause a permanent dilatation as well.
During use of the pre-fabricated construction panel, the pre-fabricated construction panel may become curved or may crack due to internal tension implied by said dilatations.